1. swelter -- (be uncomfortably hot)
2. swelter -- (suffer from intense heat; "we were sweltering at the beach")
1.
This there was no great difficulty in doing for the smack flew round steadily enough, and upon an even keel--only swaying to and fro, with the immense sweeps and swelters of the whirl. - from The Works of Edgar Allan Poe by Edgar Allan Poe